Center closing press



Sept 21, 1965 T. J. BowMAN 3,207,406

CENTER CLOSING PRESS Filed Jan. 15, 1965 Wim I'Il,

.11 TTOR NE V5,

United States Patent O 3,207,406 CENTER CLOSING PRESS Theodore J.Bowman, Opa-locka, Fla., assignor to Automated Building Components Inc.,Miami, Fla., a corporation of Florida Filed Jan. 15, 1963, Ser. No.251,632 12 Claims. (Cl. 227-152) This invention relates to a centerclosing press and more particularly to a hydraulically operated C-clamppress for driving metal connectors into structural wood joints.

Fluid operated C-clamps or vises are well known and are used in a greatmany operations for holding workpieces or material to be operated upon.In most instances. the C-clamp is itself portable and is provided with asingle movable jaw, the stationary jaw being initially placed againstone surface of the workpiece. In instances where the C-clamp isstationary or secured to a support such as a work bench or table, theworkpiece is usually brought into engagement with the stationary jaw andthe movable jaw then drawn into engagement with the other surface of theworkpiece.

The present invention relates to a C-clamp type press wherein both jawsare movable to drive metal connectors into the opposite sides of astructural wood joint. The novel press of the present invention is ofparticular utility in situations where the workpiece or material to beoperated upon is either relatively heavy or not otherwise easily movedinto engagement with the surface of one jaw of the lixed or stationarypress. In addition a novel adjustable compensating spring arrangement isprovided to assure rapid and ,uniform movement of both press jaws intodriving engagement with the workpiece. The press of the presentinvention is particularly adapted for conveyorized operation in formingthe joints of relatively large structural elements such as house rooftrusses and the like.

It is therefore one. object of the present invention to provide a novelcenter closing press.

Another object of the present invention is to provide a novel C-clamptype fluid operated press.

Another object of the present invention is to provide a novel uidoperated press for driving metal connectors into wooden joints.

Another object of the present invention is to provide a novelcompensating spring arrangement for a center closing C-clamp press.

These and further objects :and advantages of the invention will be moreapparent upon reference to the following specification, claims andappended drawings wherein:

FIGURE 1 is an elevational View of the novel press of the presentinvention;

FIGURE 2 is a side view of the press of FIGURE l; and

FIGURE 3 is a side view similar to that of FIGURE 2 with parts insection.

Referring to the drawings, the novel press of the present inventiongenerally indicated at in each of FIG- lURES 1 through 3 comprises aC-shaped frame 12, an

upper movable jaw 14 and a lower movable jaw 16. Frame 12 is made of apair of side plates 18 and 20 both of identical C-shape joined by across bar 21 and screws 22. The cross bar 21 receives screws 24 and 26which removably support the upper jaw 14 as shown in FIG- URE l. j

Resting on a table 28 or other suitable support are a pair of boards 30and 31 to be joined in an end type butt joint at 33. The boards arejoined by a pair of metal connectors such as upper connector 34 andlower connect- 3,207,406 Patented Sept. 21, 1965 ICC or 36 which may beof the type disclosed in U.S. Patent No. 2,877,520. The portions of theboards 30 and 31 to be joined extend over a cut-out section 29 in theedge of the table 28 which provides clearance for the jaws 14 and 16.

The connectors 34 and 36 are manually placed against the jaws and heldin the proper position by suitable magnets such as permanent magnets 35and 37 embedded in the jaws.

Lower jaw 16 is secured by screws 38 shown in FIG- URE 3 to a collar 40press fitted or otherwise rigidly connected to the top of a plunger orpiston 42. Piston 42 is received in a cylinder 44 in turn slidablymounted in a support tube 46. Welded to the support tube is a supportingange 48 having apertures 50 for connection by screws, bolts or the liketo a rigid, stationary base indicated by the hatching at 52.

Support tube 46 is provided with a transverse pin 54 upon which restsone end of a relatively heavy compression spring 56. The upper end ofcompression spring 56 engages the bottom 58 of cylinder 44. A supplypipe 60 passes through a suitable aperture in the wall of the cylinder44 and communicates with the interior of the cylinder. The space betweenthe bottom 58 of the cylinder and the bottom of the piston 42 is shownas filled with hydraulic iluid such as oil 62. It is apparent that otherliquids or gases such as water or air can be used to drive the press.

Pipe 60 is rigidly secured in the wall of cylinder 44 and the supporttube 46 is provided with an elongated vertical slot 64 to permit upwardand downward movement of the supply pipe 60 with upward and downwardmovement of the cylinder 44. A socket 66 internally threaded as at 68 issecured to the pipe 60 for the reception of a flexible hydraulic lineindicated diagrammatically at 70. Line 70 is connected through athree-way valve 72 to the high pressure output line 74 of a hydrauliepump 76 and to a return line 78 leading either to the sump of thehydraulic system or to the low pressure input side of the pump 76. It isunderstood that valve 72 alternatively connects the line 70 either toline 74 or to line 78, so that hydraulic fluid is alternatively suppliedto and exhausted from the oil chamber between the piston 42 and thebottom of cylinder 44.

The lower side of the C-shaped frame 12 is welded or otherwise suitablyattached to the opposite sides of a ring 80 having internal teeth 81engaging similar teeth on the upper end of cylinder 44. In this way theframe 12 is rigidly attached to and carried by the cylinder. As aresult, upward and downward movement of the cylinder 44 results inupward and downward movement of the upper jaw 14.

As best seen in FIGURES 1 and 2, a pair of tension springs 82 and 84 areconnected between the lower jaw 16 and the support flange 48. Thetension of these two springs may be adjusted by turning the locking nuts88 on the lower ends of hook bolts 90. If desired, a suitable indiciastrip 92 may be secured to one of the plates such as plate 20 foraligning the press with the top of table 28.

In operation, connector 34 is first placed against upper jaw 14 and heldin place by magnet 35. The lower connector 36 is placed on the lower jaw16 directly beneath the upper connector 34. Valve 72 is then actuatedeither manually or automatically to connect high pressure line 74 withinput'line 70 so as to supply high pressure fluid to the underside ofpist-on 42. The action of the pressure fluid is to drive the piston 42upwardly with respect to the cylinder 44and at the same time drive thecylinder 44 itself downwardly in the support pipe 46.

Upward movement of the piston 42 carrying lower jaw 16 is resisted bythe tension springs 82 while downward movement of the cylinder 44carrying the frame 12 and hence uppper jaw 14 is at the same timeresisted by the larger compression spring 56. It is preferred that thesprings be chosen so that the resistance of spring 56 is equal to thecombined resistance of both springs 82 and 84 although the selection ofthe springs is not critical. The springs acting against the oppositemovable jaws of the press provide a compensating action to assure thatboth jaws will move simultaneously towards each other to drive theplates 34 and 36 from the solid line position to the dashed lineposition illustrated in FIGURE 3 into the opposite surfaces of theboards 30 and 31. Once the connectors are completely driven, valve 72 isagain actuated, disconnecting supply line 70 from high pressure line 74and connecting to low pressure line 78. With the oil 62 in the cylinderconnected to the exhaust side of the hydraulic system, the compensatingsprings 56, 82 and 84 serve the dual purpose of return springs drawingthe piston 42 downwardly and pushing the cylinder 44 upwardly to squeezeoil from the chamber and back out through the pipe 60 and valve 72 tothe return line 78. This return movement or opening of the jaws islimited by the equilibrium position of the spring system indicated bythe rest position of the press illustrated in the respective figures ofthe drawing.

It is apparent from the above that the present invention provides anovel center closing press, particularly suited for use in driving metalconnectors into structural lumber. While the press as shown isillustrated for use in conjunction with a table supported woodstructure, it is apparent that the table 28 could be replaced by amovable conveyor with the press position adjacent the conveyor edge.Likewise, although shown utilizing hydraulic fluid, the press may beoperated with liquids other than oil -and may be pneumatically operatedif desired. Novel features of the press include movement of both jawswith respect to a stationary support so as to make it possible to driveconnectors into both the upper and lower surfaces of the wood elementsto be joined, which action is particularly advantageous for theconstruction of structural timber such as roof trusses and the likewhich are of relatively large size and are not easily movable intoengagement with one of the press jaws.

Additional important features include the provision of an adjustablecompensating spring arrangement, which springs function not only asreturn springs for the two movable jaws, but act to automaticallycompensate for the different resistant forces acting on the jaws toinsure simultaneous movement of both jaws toward and away from theworkpiece. Adjustment of the tension springs 82 and 84 by means of nuts88 makes it possible to easily modify the position at which the jawswill completely close so as to insure uniform closing movement of thejaws when lumber of a different thickness is joined in the press. Thedevice is of relatively simple, rugged construction requiring a minimumof upkeep and repair.

The simultaneous movement of both jaws provides for a minimum of jointdistortion during pressing and makes possible a strong, tight joint.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive,

the scope of the invention being indicated by the appended `claimsrather than by the foregoing description, and all y means for supplyingpressure uid between one end of said 4 cylinder and said piston to movesaid jaws substantially simultaneously toward each other. v

2. A press according to claim 1 wherein at least one of said jaws isprovided with magnetic means for holding a metal connector.

3. A press comprising a rigidly mounted support tube, a cylinder havinga closed end slidable in said support tube, a frame including a firstpress jaw carried by the other end of said cylinder, a piston slidablein said cylinder and carrying a second press jaw, and means forintroducing a pressure fluid between said piston and said closed end ofsaid cylinder to produce closing movement of said jaws.

4. A press comprising first movable means supporting a first jaw, secondmovable means spaced from said first means and carrying a second jaw,means for introducing a pressure fluid between said first and secondmeans to move said jaws substantially simultaneously toward each other,and resilient means acting against both said first and second movablemeans to resist the movement of said jaws.

5. A press for driving metal connectors comprising a movable cylinderand piston, a C-shaped frame carrying a first jaw mounted on saidcylinder, a second jaw mounted on said piston, means for moving saidcylinder and piston to move said jaws substantially simultaneouslytoward each other, and spring means acting against both said cylinderand said piston to resist the movement of said jaws.

6. A center closing press for driving metal connectors comprising astationary support, ya hollow cylinder having a closed end slidable insaid support, a C-shaped frame carrying a first jaw mounted on the otherend of said cylinder, a piston having one end slidable in said cylinder,a second jaw mounted on the other end of said piston, and means forintroducing pressure fluid between said closed end of said cylinder andsaid one end of said piston to produce closing movement of said jaws.

7. A press according to claim 6 including compression spring meansbetween said closed end of said cylinder and a portion of said supportfor resisting closing movement of said first jaw, and tension springmeans for resisting closing movement of said second jaw.

8. A press according to claim 7 wherein the resistive forces of saidtension and compression spring means are equal.

9. A center closing press` for driving metal connectors comprising asupport tube having a flange for rigidly connecting said tube to astationary support, a hollow cylinder having a closed end slidable insaid support tube, a C-shaped frame carrying a first jaw mounted on theother end of said cylinder, a piston having one end slidable in saidcylinder, a second jaw mounted on the other end of said piston, meansfor introducing pressure between said closed end of said cylinder andsaid one end of said piston to produce closing movement of said jaws, ,acompression spring bearing against said closed end of said cylinder forresisting closing movement of said first jaw, and a pair of tensionsprings coupling said flange to said second jaw for resisting closingmovement of said second jaw.

10. A press according to claim 9 including permanent magnets in saidjaws for holding metal connectors.

11. A center closing press for driving metal connectors comprising avertical support tube having a flange for rigidly connecting said tubeto a stationary support, a hollow cylinder having a closed lower endtelescopingly received in the upper end of said support tube, avertically extending C-shaped frame mounted on the upper end of saidcylinder and carrying an upper press jaw, a piston having its lower endtelescopingly received in the upper end of said cylinder, a lower pressjaw mounted on the upper end of said cylinder in vertical alignment withsaid upper press jaw, means for introducing la hydraulic pressure fluidbetween the lower ends of said piston and cylinder to produce closingmovement of both said jaws, stop means in the lower end of said supporttube, a compression spring between said stop means and the lower end ofsaid cylinder for resisting downward movement of said upper press jaw,land a pair of tension springs connected between said lower jaw and saidange for resisting upward movement of said lower jaw.

12. A press according to claim 11 wherein said support tube is providedwith an elongated vertical slot, and said hydraulic pressure iluidintroducing means comprises a feed tube communicating with the interiorof said cylinder and passing through said slot.

References Cited by the Examiner UNITED STATES PATENTS Spaulding100--264 X Purcell 1GO- 269 Osborne et al. 1-44.4 Juilfs 1-44.4Moehlenpah et al. 1 149 10 GRANVILLE Y. CUSTER, JR., Primary Examiner.

6. A CENTER CLOSING PRESS FOR DRIVING METAL CONNECTORS COMPRISING ASTATIONARY SUPPORT, A HOLLOW CYLINDER HAVING A CLOSED END SLIDABLY INSAID SUPPORT, A C-SHAPED FRAME CARRYING A FIRST JAW MOUNTED ON THE OTHEREND OF SAID CYLINDER, A PISTON HAVING ONE END SLIDABLE IN SAID CYLINDERA SECOND JAW MOUNTED ON THE OTHER END OF SAID PISTON, AND MEANS FORINTRODUCING PRESSURE FLUID BETWEEN SAID CLOSED END OF SID CYLINDER ANDSAID ONE END OF SAID PISTON TO PRODUCE CLOSING MOVMENT OF SAID JAWS.